Stainless steel vacuum flask



FIG. 1 is a perspective view of front, top and right side of a stainless steel vacuum flask showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top plain view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a left side view thereof; and,

FIG. 8 is a perspective view of a stainless steel vacuum flask in the open condition. 

The ornamental design for a stainless steel vacuum flask, as shown and described. 